CDECK  ID>, HWULDO.

*CMZ :-        -26/04/91  11.11.56  by  Bryan Webber

*-- Author :    Bryan Webber

C----------------------------------------------------------------------

      FUNCTION HWULDO(P,Q)

C----------------------------------------------------------------------

C   LORENTZ 4-VECTOR DOT PRODUCT

C----------------------------------------------------------------------

      DOUBLE PRECISION HWULDO,P(4),Q(4)

      HWULDO=P(4)*Q(4)-(P(1)*Q(1)+P(2)*Q(2)+P(3)*Q(3))

      END